JP6319948B2 - Recording device - Google Patents

Description

The present invention relates to a recording apparatus.

  In a recording apparatus that performs recording by scanning the recording head with respect to the recording medium, the posture of the recording head during scanning is changed due to, for example, an assembly error of a guide member that guides the movement of the recording head for scanning. May occur. Due to the change in the posture of the recording head, for example, in an ink jet recording head, the landing position of the ink ejected from the recording medium deviates from the original position, and the position of the ink dots formed on the recording medium shifts. This causes a recording position shift.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a method for reducing a recording position shift caused by a change in posture of a recording head. Specifically, a sensor for detecting a change in posture of the recording head is provided, and the posture of the recording head is corrected by a piezoelectric element in accordance with the detection result of the sensor to reduce the recording position deviation.

JP 2007-090875 A

  However, when detecting the change in posture of the recording head with a sensor as in Patent Document 1, there is a problem that only the change in posture in a certain direction can be detected. That is, when there is a cause of posture variation in a plurality of directions and a recording position shift in one direction occurs, the detection of posture variation by the sensor disclosed in Patent Document 1 cannot cope with it.

An object of the present invention is to provide a recording apparatus capable of appropriately reducing a recording position shift due to a posture change regardless of the cause of the posture change of the recording head.

For this purpose, the recording apparatus according to the present invention includes a first nozzle row in which a plurality of nozzles that eject ink droplets are arranged along the first direction, and the first nozzle in a second direction that intersects the first direction. A recording head having a second nozzle array that is arranged at a position different from the array and in which a plurality of nozzles that eject ink droplets are arrayed along the first direction; and mounting the recording head in the second direction A rail that is movable to the carriage, a rail member that guides the carriage, a first support member that supports the rail member, and a rail member that is disposed at a position different from the first support member in the second direction. A second support member for supporting the recording medium, a platen disposed at a position facing the recording head and supporting the recording medium, a nozzle included in the first nozzle row, and a nozzle included in the second nozzle row And pattern recording means for recording a test pattern at each of a plurality of different positions in the second direction on the recording medium, and the test pattern recorded at each of the plurality of positions arranged on the carriage. A recording apparatus comprising: reading means for reading; and changing means for changing an angle of the recording head with respect to the platen by rotating the recording head, based on a result of reading the test pattern by the reading means And a control means for changing the angle of the recording head at a position corresponding to each of the plurality of positions by the changing means, and the second between the first nozzle row and the second nozzle row. The distance in the direction is half the distance in the second direction between the first support member and the second support member. Characterized in that it is a distance below.

  According to the above configuration, it is possible to appropriately reduce the recording position shift due to the posture variation regardless of the cause of the posture variation of the recording head.

1 is a perspective view for explaining a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 3 is a diagram schematically illustrating a configuration of an optical sensor for detecting the density of a patch in the recording apparatus according to the embodiment of the invention. FIG. 2 is a diagram illustrating a configuration of a carriage used in an embodiment of the present invention and an arrangement of nozzle rows for each color ink in a recording head mounted on the carriage. It is a figure explaining the attitude | position fluctuation | variation of the carriage 100 shown in FIG. FIG. 6 is a diagram illustrating a landing position shift in the Y direction that occurs between nozzle rows of two color inks due to a posture change caused by rolling of a carriage, that is, a recording head. (A) And (b) is a figure explaining the change of the shape of a main rail, and the recording position shift according to it. FIG. 3 is a side cross-sectional view schematically showing the carriage and the configuration for posture correction of the embodiment of the present invention. It is a top view which shows the shape of the cam attached to the pulse motor shown in FIG. 6 is a flowchart illustrating a carriage posture correction control amount calculation process according to an embodiment of the present invention. (A)-(c) is a figure showing the state where the patch concerning one embodiment of the present invention was recorded. It is a figure which shows the patch group comprised by arranging the some patch from which the deviation | shift amount shown to Fig.10 (a)-(c) differs. It is a figure which shows a sensor output when each patch which comprises one patch group shown in FIG. 11 is detected with a sensor. (A)-(c) is a figure which shows the recording of the test pattern comprised by a some patch group by the relationship with the main rail which guides the movement of a carriage. It is a figure which shows the recording positional relationship of the patch group of the main rail support member and subrail support member which concern on embodiment of this invention. FIG. 4 is a diagram illustrating a positional relationship between the arrangement of nozzle groups of a recording head used in an embodiment of the present invention and a main rail and a sub rail. It is a figure which shows the landing position shift | offset | difference of the printing dot by a preceding nozzle row, and the printing dot by a succeeding nozzle row in embodiment of this invention. (A) And (b) is a figure which shows the change of the positional relationship by the attitude | position fluctuation | variation with the nozzle which records the main rail test pattern in embodiment of this invention. (A)-(c) is a figure explaining the drive amount of the actuator which acts so that the attitude | position fluctuation | variation of a carriage may be canceled in embodiment of this invention. It is a block diagram which shows the structure for carriage attitude | position correction control based on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view for explaining a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. In FIG. 1, a carriage 100 is equipped with a recording head and can be moved in the X direction, which is the main scanning direction, and in the opposite direction by the power of a carriage motor (not shown). As a result, the recording head scans the recording medium, and ink can be ejected according to the recording data during the scanning. The main rail 101 is provided so as to extend in the main scanning direction in the apparatus, thereby guiding and supporting the movement of the carriage 100 in the main scanning direction. Both ends of the main rail 101 are fixed to the upper housing, and are supported from below by a plurality of main rail support members 103. Thereby, the deflection of the intermediate portion due to the weight of the main rail 101 itself can be suppressed. The sub rail 102 is provided in parallel with the main rail 101 and plays a role of maintaining the posture of the carriage 100 guided by the main rail 101. Similarly, the subrail 102 is also fixed to the upper housing 106 by a plurality of subrail support members 104, thereby suppressing deflection of the intermediate portion due to the weight of the subrail itself.

  The carriage encoder 105 is provided in parallel with the main rail 101, while the carriage 100 is equipped with a carriage encoder sensor (not shown). As a result, the carriage encoder sensor reads the carriage encoder 105, so that the position in the movement of the carriage 100, that is, the position in scanning of the recording head can be detected.

  The platen 106 is constituted by a flat plate, and thereby can support the recording medium from below at a position where recording can be performed by the recording head. A recording medium (not shown) is conveyed on the platen 106 in the sub-scanning direction (Y direction) by rotation of a conveying roller (not shown). The platen 106, the conveyance roller, and the like are attached to the lower housing 108. The main elements of the recording apparatus according to the present embodiment are configured by combining the configuration of the upper casing 107 and the configuration of the lower casing 108 described above.

  FIG. 2 is a diagram schematically illustrating the configuration of an optical sensor for detecting the density of a patch in the recording apparatus of the present embodiment. The optical sensor 202 is mounted on the carriage 100 and optically detects the density of a patch, which will be described later, recorded on the recording medium 201 as the carriage moves. The sensor 102 includes a light emitting unit 203 and a light receiving unit 204. Light emitted from the light emitting unit 203 is reflected by an object, and the light receiving unit 204 detects this reflected light. Reflection by the object includes regular reflection and irregular reflection. In order to detect the density of the image recorded on the object, that is, the recording medium 201 more accurately, it is desirable to detect the irregularly reflected light. Therefore, the light receiving unit 204 of the optical sensor 202 according to the present embodiment is provided at a position away from the reflection angle of the incident light 205.

  FIG. 3 shows a configuration of the carriage 100 used in the present embodiment and a nozzle row (printing element row) in which nozzles (printing elements) of the respective color inks arranged in the Y direction are arranged in the printhead 301 mounted on the carriage 100. FIG. The carriage 100 can move in the X direction in the figure and the opposite direction while being supported by the main rail 101 and the sub rail 102. At this time, the two carriage bearing members 302A and 302B connect the carriage 100 and the main rail 101, and the two sub rail receiving members 303A and 303B connect the carriage 100 and the sub rail 102. Here, when the main rail 101 is bent, the bending acts on the carriage 100 and thus the recording head via the two carriage bearing members 302A and 302B to generate the posture variation. Further, when there is a deflection of the subrail 102, this deflection similarly acts on the recording head via the subrail receiving members 303A and 303B to cause the posture variation. Such a posture variation usually appears as a final posture variation of the recording head due to a combination of the deflection of the main rail 101 and the sub rail 102 acting on the recording head.

  The bending of the main rail 101 is suppressed by the plurality of main rail support members 103, and the bending of the sub rail 102 is suppressed by the plurality of sub rail support members 104. However, depending on the distance between the support members, a slight deflection that cannot be suppressed may remain. In addition, the main rail 101 and the sub rail 102 may be slightly bent depending on the manufacturing process and assembly process of the rails.

  In the carriage 100 of this embodiment, two recording heads 301 are mounted in the main scanning direction, and each recording head 301 is provided with nozzles that eject a plurality of colors of ink. A plurality of nozzles for each color ink are arranged on a straight line in the Y direction to form one nozzle row. In the present embodiment, four nozzle rows are arranged in the main scanning direction for each color ink (not shown), and these form a nozzle group that ejects one ink color. In this embodiment, as shown in the drawing, a nozzle group of six colors of ink is arranged in the main scanning direction in one recording head. In the figure, a nozzle group for ejecting ink of PC: photocyan, C: cyan, MBk: matte black, Y: yellow, M: magenta, PM: photomagenta is arranged on the left recording head 301 from the left. ing. On the other hand, on the right recording head 301, nozzle groups for ejecting inks of R: red, G: green, B: blue, PGy: photo gray, Gy: gray, PBk: photo black are arranged from the left side. . In the recording head of this embodiment, the inter-nozzle distance D1 between adjacent ink color nozzles is 3.471 [mm], and the inter-nozzle distance D2 between the color nozzles at both ends of one recording head is 24. It is 298 [mm]. Further, the inter-nozzle distance D3 between the color nozzles at both ends of the two recording heads is 100.498 [mm].

  FIG. 4 is a diagram for explaining the posture variation of the carriage 100 shown in FIG. 3 and the like, and the example shown in the drawing shows the posture variation that may occur when the carriage moves along the main rail 101. The posture variation shown in FIG. 4 can also occur when the carriage moves along the subrail 102. Here, three X-axis, Y-axis, and Z-axis that are orthogonal to each other and serve as a reference for explaining the posture variation are defined as follows. In the example shown in the figure, which causes the posture variation, the imaginary straight axis of the main rail 101 is the X axis. Further, an axis passing through the center of the surface of the carriage 100 facing the main rail and intersecting the X axis is defined as a Y axis. An axis intersecting the X axis and the Y axis is taken as a Z axis. As can be seen from this definition, the Y axis and the Z axis move as the carriage 100 moves.

  In the following description, for example, a case where the main rail 101 is curved in the Z direction and the sub rail 102 is not deformed such as curved is considered. In this case, when the carriage 100 moves, the posture of the carriage changes in the Z direction according to the curvature thereof. At this time, since the subrail 102 is not deformed, the carriage having the subrail 102 as an axis by the change in the Z direction. This causes rotation. In this case, since the rotation angle is relatively small, in the example shown in FIG. 4, this rotation is referred to as a posture change (hereinafter referred to as “rolling”) due to the rotation about the main rail 101. Represents. Further, a posture change (hereinafter, this posture change is referred to as “pitching”) that rotates around the Y-axis due to the curvature in the Z direction may occur. Further, when the main rail 101 is curved in the Y direction, a posture variation (hereinafter, this posture variation is referred to as “yawing”) in which the carriage 100 rotates around the Z axis may occur. In the recording apparatus of the present embodiment, it is assumed that the carriage posture variation (yawing) caused by the main rail being curved in the Y direction is suppressed by adjusting the accuracy of the main rail.

  FIG. 5 is a diagram illustrating a landing position deviation in the Y direction that occurs between nozzle rows of ink of two colors due to a change in posture due to rolling of the carriage, that is, the recording head. A nozzle (row) positioned forward in the carriage movement direction is a preceding nozzle (row), and a nozzle (row) positioned rearward of the preceding nozzle row is a trailing nozzle (row). FIG. 5 shows a case where the carriage moves from left to right. When ink is ejected at the same position on the recording medium (the same position of the carriage position), after the dot 600 is recorded by ejecting ink from the preceding nozzle, the carriage moves by a distance 602 between the preceding nozzle and the succeeding nozzle. The dots 601 are recorded by ejecting ink from the succeeding nozzle. In this case, while the carriage moves through the inter-nozzle distance 602, the above-described carriage posture change occurs, and as a result, landing in the Y direction occurs between the dot 600 by the preceding nozzle and the dot 601 by the succeeding nozzle. A recording position shift of a shift amount 603 occurs.

  The example shown in FIG. 5 shows the landing position deviation caused by the posture fluctuation only by rolling as described above. This landing position deviation is caused by the plural kinds of posture fluctuations of the recording head described above with reference to FIG. It can be assumed that the displacement due to is synthesized. That is, in the embodiment of the present invention, as will be described later, a test pattern composed of patches is recorded in advance, and the landing position deviation in one direction such as the Y direction is determined based on the recording density detected for the patch. To detect. For this reason, in the recorded patch, a combination of positional deviations caused by a plurality of types of posture variations with respect to the recording head occurring at that time can appear. In the embodiment of the present invention, the posture of the carriage is corrected so as to suppress the synthesized positional deviation. In addition, in the apparatus that includes the two guide members of the main rail and the sub rail and moves the carriage as in the present embodiment, the recording position deviation due to the posture variation caused by the distortion of each of the two guide members is also synthesized. Of course, it can be expressed as the density value of the patch.

  FIGS. 6A and 6B are diagrams for explaining the change in the shape of the main rail and the recording position shift corresponding thereto. Here, FIG. 6A shows an example of the shape change of the main rail, and FIG. 6B shows a state when the carriage is moved when the shape change shown in FIG. 6A occurs. The recording position shift by two nozzles is shown. As described above with reference to FIG. 3, the distance D3 between the nozzle row of the ink PBk and the nozzle row of the ink PC is approximately equal to the distance D2 between the nozzle row of the ink PBk and the nozzle row of the ink R. 4 times longer. Therefore, in general, the combination of nozzles having a longer inter-nozzle distance increases the relative landing deviation due to the height fluctuation of the main rail. In addition, the relative landing deviation due to the height fluctuation of the sub rail can be said to be the same as that of the height fluctuation of the main rail.

  FIG. 7 is a side cross-sectional view schematically showing the carriage of this embodiment and a configuration for correcting its posture. The carriage 100 includes a recording head storage unit 800 on which the recording head 301 is mounted. The recording head storage unit 800 is attached to the carriage 100 so as to be rotatable about the shaft 801. Further, a pulse motor 802 is attached to the carriage 100, and this motor provides a driving force for correcting the posture of the carriage. That is, the cam 803 is attached to the pulse motor 802, whereby the upper end portion of the recording head storage portion 800 can be displaced in the Y direction. Due to the displacement in the Y direction due to the action of the cam 803, the recording head storage portion 800 can rotate in the θ direction about the shaft 801. Note that the rotational position of the recording head storage unit 800 is determined by the stop position of the cam 803. This displacement point is assumed to be located at the center with respect to the size of the carriage in the main scanning direction.

  FIG. 8 is a diagram showing the shape of a cam attached to the pulse motor shown in FIG. The cam 803 has a different linear distance from the center of rotation to the circumference depending on the rotation angle. A displacement is generated at the contact point of the circumference, and the recording head storage unit is rotated. A position reference plate 900 is attached to the cam 803, and an edge portion of the position reference plate 900 is detected as a reference position by a photo interrupter attached to the carriage. Both edge portions of the position reference plate 900 are a minimum displacement point 901 and a maximum displacement point 902 generated by the cam, respectively.

  FIG. 9 is a flowchart showing a carriage posture correction control amount calculation process according to an embodiment of the present invention.

  When the carriage posture correction control amount calculation processing mode is activated, first, in step S1, the width of a recording medium for recording a test pattern to be described later is detected using the optical sensor 202. Since the amount of reflected light from the light emitting unit 203 differs greatly between the area where the recording medium is fed and the area where the platen is exposed, the presence or absence of the recording medium, that is, the width of the recording medium is measured by detecting these. be able to. At this time, the sensitivity adjustment of the optical sensor 202 may be continuously performed using the blank area of the recording medium. Specifically, the carriage is moved to a position where the optical sensor 202 detects a blank area, and the detection amplifier of the light receiving unit 204 is adjusted until the detection signal from the light receiving unit 204 reaches a predetermined upper limit value. The amount of reflected light incident on the light receiving unit 204 varies depending on the type of recording medium. The amount of received light also changes depending on the distance from the recording medium. Therefore, by performing such sensitivity adjustment using a recording medium that records the test pattern before detecting the actual test pattern, the S / N ratio is improved, and the relative density of each patch is adjusted. It becomes possible to acquire in a more sensitive state. However, such sensitivity adjustment of the optical sensor 202 is not always necessary. Also, the width of the recording medium does not necessarily have to be detected using the optical sensor 202, and the user may specify the paper size.

  In addition, the recording apparatus of the present embodiment is a relatively large apparatus, and can perform recording on a large format recording medium. However, the recording apparatus can also be used when a narrower roll paper is used. . In such a case, it is not necessary to prepare a relatively wide recording medium only for the attitude correction control amount calculation process. The roll paper is fed and transported in a blank state where no recording operation is performed, and is cut at a position corresponding to the length of the scanning area of the carriage, and the length direction of the cut roll paper is set as the scanning area. At the same time, it can be fed again into the apparatus.

  In the next step S2, a predetermined test pattern is recorded on the fed recording medium.

  FIGS. 10A to 10C are diagrams illustrating a state in which patches according to the present embodiment are recorded, and illustrate patches in which the amount of positional deviation of dots recorded by the preceding nozzle and the succeeding nozzle is different. . In the figure, a white circle 1100 indicates a dot recorded by the preceding nozzle, and a gray circle 1101 indicates a dot recorded by the subsequent nozzle.

  FIG. 10A shows a patch in a state where a shift corresponding to four pixels is generated at the recording positions of the preceding nozzle and the succeeding nozzle. FIG. 5B shows a patch in a state where a shift corresponding to two pixels is generated between the preceding nozzle and the succeeding nozzle. FIG. 10C shows the patch of the preceding nozzle and the succeeding nozzle. A patch in a state where a shift corresponding to one pixel is generated between the two is shown. As described above, the plurality of patches of the test pattern are recorded by artificially changing the recording position shift corresponding to the angular displacement of the recording head in the predetermined direction by a predetermined amount. In the present embodiment, the change in the deviation amount is realized by making the ejection nozzles in the sub-scanning direction of the succeeding nozzles different from the preceding nozzles.

  FIG. 11 is a diagram illustrating a patch group configured by arranging a plurality of patches having different shift amounts as described above. In the figure, a to f indicate patches of about 10 mm square in which the displacement amounts of the discharge nozzles of the preceding nozzle and the succeeding nozzle are varied in six stages, and one patch group 1201 is composed of six patches a to f. Forming. These are recorded on the recording medium 201 by reciprocating scanning of the recording head.

  FIG. 12 is a diagram showing sensor outputs when each of the six patches a to f constituting one patch group shown in FIG. 11 is detected by a sensor. In the example shown in the figure, the patch d has the lowest density (high brightness) and no deviation. Then, the measurement results (sensor outputs) of the six patches a to f are approximated by a predetermined function, and the deviation amount corresponding to the density when the sensor output is the smallest, that is, the density is the highest from the approximation results. The amount of deviation of the patch group 1201 is obtained. In this way, for one patch group, the deviation amount of one landing position in the area where the patch group is recorded is calculated.

  FIGS. 13A to 13C are diagrams illustrating the recording of the test pattern 1400 configured by the plurality of patch groups 1201 in relation to the support member of the main rail. FIG. 13A shows one patch group 1201. This patch group 1201 is configured by arranging patches a to f in the main scanning direction as shown in FIG. 13B. is there. The individual patches a to f correspond to the patches a to f described above with reference to FIG. FIG. 13C shows an example in which one test pattern 1400 is recorded so that four patch groups are recorded between the support members of the main rail. In the present embodiment, four patch groups are recorded between the main rail support members. However, a larger number of patch groups may be recorded between the main rail support members, thereby enabling more accurate recording. It is possible to detect the amount of displacement.

  FIG. 14 is a diagram illustrating the recording position relationship of the patch group 1201 between the main rail support member 103 and the subrail support member 104. In the present embodiment, four patch groups 1201 are recorded during the interval D6 at which the distance between the main rail support member and the sub rail support member is minimized. In a normal case where the curvature increases as the main rail or the sub rail moves away from the support members, the carriage posture variation is caused by the interval D6 between the main rail support member 103 and the sub rail support member 104, or the two main rail support members. It occurs with a period slightly shorter than the interval D7. For this reason, it is desirable to record as many patch groups as possible between the main rail support member and the sub rail support member and between the two main rail support members. In this embodiment, four patch groups are recorded.

  If there are many locations where the recording position deviation should be measured and the interval is smaller than the width of the patch group 1201, the recording medium is transported to the position shifted in the sub-scanning direction. A plurality of patch groups 1201 may be arranged. Accordingly, each patch group can be arranged at an appropriate position without reducing the size of each patch. In the present embodiment, a plurality of patch groups are recorded between the main rail support member 103 and the subrail support member 104 to form one test pattern 1400.

  FIG. 15 is a diagram illustrating the positional relationship between the arrangement of the nozzle groups of the recording head 301 used in the present embodiment and the main rail 101 and the sub rail 102. When the ink dots are overlapped and recorded by the nozzles of a plurality of color inks, if the posture variation of the recording head is the pitching or yawing described above with reference to FIG. The landing deviation in between increases. Here, as the landing deviation between dots is larger, the detection accuracy by the optical sensor is improved. However, if a recording head having a longer inter-nozzle distance than the most common rail bending cycle is used, it is difficult to accurately detect the posture change of the recording head. Since the curve of the rail occurs at the interval between the rail support members, the recording of the test patch in this embodiment uses two nozzles (rows) relatively positioned at a distance equal to or less than half of the interval between the rail support members. It is desirable.

  Further, since the rolling of the carriage occurs with the main rail and the sub rail as axes, the nozzles farthest from the main rail and the sub rail are most affected by the rolling, and the relative landing deviation increases. Therefore, it is desirable to use the nozzles in the range of the nozzle group D5 located farthest from the main rail and the sub rail with respect to the nozzle array D4 in the recording medium conveyance direction for patch recording.

  Referring to FIG. 9 again, when the recording of the test pattern in step S2 is completed, in step S3, the carriage is moved at a low speed with respect to the test pattern recorded on the recording medium, and each patch is recorded using an optical sensor. Detect the concentration. As described above with reference to FIG. 12, approximation by a predetermined function curve is performed from the detected densities of a plurality of patches (patch groups) to obtain a recording position deviation amount. Therefore, one recording position deviation amount is obtained for one patch group, and hence one position. As described with reference to FIG. 10, the used nozzle range of the subsequent nozzle row is shifted by a predetermined number of pixels in the sub-scanning direction, and the patch is recorded. This shift direction can determine the shift direction of the recording position shift amount. .

  Next, in step S4, the inclination amount of the carriage (recording head) is calculated based on the recording position deviation amount and the deviation direction obtained in step S3. That is, the posture of the recording head is acquired.

FIG. 16 is a diagram illustrating a recording position shift between the recording dot 600 by the preceding nozzle row and the recording dot 601 by the subsequent nozzle row. A recording position shift amount between the preceding nozzle recording 600 and the succeeding nozzle recording 601 is Tz. With the preceding nozzle record 600 as a reference, the case where the succeeding nozzle record 601 is displaced in the paper transport direction is regarded as plus, and conversely, the case where the succeeding nozzle record 601 is displaced toward the sheet feeding side is regarded as minus. . That is, with respect to the preceding nozzle record 600, when the succeeding nozzle record 601 is shifted in the paper transport direction, it is + Tz, and in the opposite case, it is −Tz and has a sign. A recording position shift amount having this code is represented as Iz. Therefore, Iz is
Iz = ± Tz Formula 1
It can be expressed as.

  FIGS. 17A and 17B are diagrams showing a change in the positional relationship between the main rail 101 and the nozzle 1800 for recording the test pattern due to a change in posture in the embodiment of the present invention. The variables shown in FIG. 17 are as follows.

MN _Y : transport direction distance between main rail and nozzle MN _L : distance between main rail and nozzle MN _θ : angle formed by straight line MN _Y and straight line MN _L P: distance between nozzle of print head and print medium B: Angle of change in posture of the recording head when recording with the succeeding nozzle, based on the time when recording with the preceding nozzle. FIG. 17A shows the posture of the recording head when recording the test pattern patch. The reference of the angle change by the attitude | position fluctuation | variation in which the recording medium and the recording head were located in parallel is shown. On the other hand, FIG. 17 (b) shows a state rotated by an angle (A + B) from the reference shown in FIG. 17 (a). That is, assuming that the angle of the recording head when recording with the preceding nozzle is A, if the recording head is further rotated by an angle B when recording with the succeeding nozzle from the recording with the preceding nozzle, the amount of inclination from the reference Becomes (A + B). In this embodiment, the difference B in the amount of inclination is calculated as the amount of inclination of the carriage (recording head) for each patch. Then, as will be described later with reference to step S5 in FIG. 9, the posture of the recording head is changed so as to cancel the tilt amount B. The equation for deriving the tilt angle B of the recording head is as follows in the relationship shown in FIGS.

In the above equation and FIG. 17B, Ajet and Bjet represent the Y coordinate of the dot position recorded by the recording head having the above-described angles A and B, respectively. The dot misregistration amount Iz due to can be expressed as Bjet-Ajet. Then, by using an approximation assuming that the angles A and B are relatively small angles, it can be expressed as Ajet = MN _L cos (MN _θ + A) + PsinA. Using this relationship, the inclination amount B can be finally obtained by the above equation 2.

  Refer to FIG. 9 again. When the carriage tilt amount is calculated in step S4, in step S5, the actuator drive amount that works to offset the carriage posture variation is calculated from the carriage tilt amount obtained in step S4.

  FIG. 18A shows the positional relationship between the displacement point where the force is applied by driving the attitude control actuator and the nozzle used for test pattern recording. FIG. 18B is the same as FIG. FIG. FIG. 18C is a diagram when rolling is generated around the shaft by driving the pulse motor 802 which is an attitude control actuator.

As shown in FIG. 18C, the displacement angle AC _θ for canceling the inclination amount B obtained by the above equation 2 is expressed by the following equation 3.

Then, the driving amount of the actuator for realizing the displacement angle AC _θ can be obtained from the relationship shown in FIGS. 18A and 18B by the following expression 4. That is, in this embodiment, by driving the pulse motor 802 causes a displacement AC _Y in the conveying direction of the recording medium (Y direction) by a cam 803 attached to the pulse motor, thereby, the shaft 801 as an axis The recording head 301 is displaced by an angle Acθ.

Here, JA _Y is the distance in the conveying direction between the shaft and the displacement point, JA _L is the distance between the shaft and the displacement point, and JA _θ is the angle formed by JA _Y and JA _L. This drives the pulse motor in the driving amount AC _Y as determined by equation 4, it is possible to suppress the attitude change of the carriage.

  Refer to FIG. 9 again. When the actuator drive amount is calculated in step S5, in step S6, the actuator drive amount for each carriage position obtained in step S5 is stored in the ROM in the apparatus. At this step, the posture correction control amount calculation process is completed.

  FIG. 19 is a block diagram showing a configuration for carriage posture correction control according to the embodiment of the present invention described above. The motor control configuration includes a motor position control circuit 2000 and a motor control arithmetic circuit 2001.

  In FIG. 19, the initial position of the motor is detected by using a cam position detection sensor 2002 including a position reference plate 900 attached to the cam and a photo interrupter. The result of the cam position detection sensor is processed by the motor position control circuit 2000, and the motor is controlled to the initial position.

  When the recording head is scanned and recording is performed on the recording medium, the position of the carriage is detected using the carriage encoder sensor 2003, and the motor drive amount at the carriage position is read from the ROM 2004. The motor control arithmetic circuit 2001 generates a pulse signal from the read drive amount and inputs the generated pulse signal to the motor driver 2005 to drive the motor 2006. The motor 2006 is attached with the cam shown in FIG. 8, and as described above, the displacement is generated in the direction to cancel the carriage posture variation, and the head is rolled to perform carriage posture correction control.

  As described above, according to the embodiment of the present invention, the posture variation correction is performed on the carriage being recorded, and the carriage is scanned in a constant posture, thereby suppressing the dot recording position shift caused by the carriage posture variation. The recording image quality can be improved. Further, since the posture change of the carriage is detected and the posture change is suppressed, a slight curve of the carriage rail can be allowed. In other words, at the same time as improving the recording image quality, it is possible to reduce an increase in cost (product price) for selecting a carriage rail member that does not bend and improving assembly accuracy.

  Such an effect is particularly remarkable in a large recording apparatus. That is, the recording position shift according to the embodiment of the present invention becomes conspicuous in a large recording apparatus that can perform recording on a relatively large recording medium. In the case of a relatively small recording apparatus, such a change in posture of the recording head is small, and there is little problem in the recorded image. On the other hand, in the case of a large recording apparatus, the scanning distance of the recording head is long. For example, even if the guide rail for guiding and supporting the carriage in the main scanning direction has a slight warp, the posture variation of the recording head becomes large. Because.

  The application of the present invention is not limited to the ink jet recording apparatus described as the embodiment of the present invention, and it is clear from the above description.

DESCRIPTION OF SYMBOLS 100 Carriage 101 Main rail 102 Sub rail 103 Main rail supporting member 104 Sub rail supporting member 201 Recording medium 202 Optical sensor 301 Recording head 302A, 302B Carriage bearing member 303A, 303B Sub rail receiving member 801 Shaft 802 Pulse motor 803 Cam 2000 Motor position control circuit

Claims (9)

A plurality of nozzles that eject ink droplets are arranged along the first direction, and the ink droplets are arranged at positions different from the first nozzle row in a second direction that intersects the first direction. A recording head having a second nozzle array in which a plurality of nozzles for discharging the nozzle are arranged along the first direction;
A carriage mounted with the recording head and movable in the second direction;
A rail member for guiding the carriage;
A first support member for supporting the rail member;
A second support member arranged at a position different from the first support member in the second direction and supporting the rail member;
A platen disposed at a position facing the recording head and supporting a recording medium;
Pattern recording means for recording a test pattern at each of a plurality of different positions in the second direction on the recording medium using the nozzles included in the first nozzle array and the nozzles included in the second nozzle array When,
A reading unit arranged on the carriage and reading the test pattern recorded at each of the plurality of positions;
Changing means for changing an angle of the recording head with respect to the platen by rotating the recording head,
And further comprising a control means for changing the angle of the recording head at a position corresponding to each of the plurality of positions by the changing means based on a result of reading the test pattern by the reading means.
The distance in the second direction between the first nozzle row and the second nozzle row is not more than half of the distance in the second direction between the first support member and the second support member. A recording apparatus characterized by being a distance. A second rail member arranged at a position different from the rail member in the first direction and guiding the carriage;
A third support member for supporting the second rail member;
A fourth support member that is arranged at a position different from the second support member and the third support member in the second direction and supports the second rail member;
2. The pattern recording unit records a plurality of the test patterns between the second support member and the fourth support member in the second direction on the recording medium. Recording device.   The pattern recording means records at least four of the test patterns between the second support member and the fourth support member in the second direction on the recording medium. The recording device described. Said pattern recording means, the recording medium on at least the third of the test pattern in the position corresponding to the fourth supporting member and a position corresponding to the support member, characterized in that the recording claim 2 or 4. The recording apparatus according to any one of items 3.   The pattern recording means records the test pattern at a position corresponding to at least the first support member and a position corresponding to the second support member on the recording medium. 5. The recording device according to any one of 4 above.   The pattern recording means uses a plurality of nozzles including nozzles at positions farthest from the rail member in the first direction among the nozzles included in the first nozzle row and the second nozzle row, The recording apparatus according to claim 1, wherein the test pattern is recorded.   The test pattern includes a plurality of patches recorded by shifting a nozzle included in the first nozzle row and a nozzle included in the second nozzle row by a predetermined amount in the first direction. The recording apparatus according to any one of claims 1 to 6.   The recording apparatus according to claim 1, wherein the reading unit is an optical sensor, and the density of the test pattern is detected by the optical sensor. A calculation unit that calculates an amount of inclination of the recording head with respect to the platen at a position corresponding to each of the plurality of positions based on a reading result of the test pattern by the reading unit;
2. The control unit according to claim 1, wherein the angle of the recording head at a position corresponding to each of the plurality of positions is changed by the changing unit based on the inclination amount calculated by the calculating unit. 9. The recording apparatus according to any one of items 8 to 8.